( 19 ) 



more or less covered with air-bubbles. Thpy are capable of 

 remaining thirty minutes or more below the surface, clinging 

 to plants and submerged weeds. It is possible that in suitable 

 situations the females enter the water to oviposit, but this 

 would be impossible where the stream runs swiftest, and in 

 such places it is possible that they lay their eggs on the wet 

 rocks along the edge of the water. We were not fortunate 

 enough to observe the method of oviposition of the parasite." 

 The use of the Saw by a Sawply during Oviposition. — 

 Professor Poulton said that he had noticed the discussion at 

 a previous meeting upon the " saw " of the female Sawfly, and 

 observed that there was but little direct evidence of its use. 

 He therefore thought it might be of interest to record that 

 about the year 1886 he had watched the female of Croesus 

 septentrionalis, L., ovipositing on the under surface of a birch 

 leaf, in his garden at Oxford. Some of the ova then laid were 

 exhibited to the meeting, preserved in spirit. The speaker 

 had been much struck with the deliberate movements of the 

 insect and the facility with which she could be approached 

 and examined with a lens Vithout any interference with her 

 work. He distinctly remembered the saw being moved back- 

 wards and forwards as in the ordinary act of sawing, but 

 could not be sure whether the work was done in the pull (as 

 in certain pruning saws) or the push (as in most saws). The 

 effect was to cut a slit in the leaf tissue beside and obliquely 

 to the axis of the midrib or some chief vein. The saw was 

 xlv] 



then withdrawn and a sausage-shaped egg laid in the slit : an- 

 other slit was cut parallel with and immediately below the last, 

 and another egg laid. The operation was repeated until a long 

 row of obliquely-placed eggs lay like a seam beside the midrib 

 or vein. He had watched the rapid swelling of the eggs thus 

 laid, probably by absorption from the leaf tissues, and had 

 preserved examples at various stages up to the point at which 

 the larvae hatched. These were exhibited to the meeting. 



xlix] Wednesday, October 6th, 1909. 



Breeding experiment with Charaxes. — Mr. G. F. Leigh 



exhibited the $ parent and 21 specimens of the offspring of \0 



